This invention relates generally to self propelled devices for cleaning submerged surfaces such as found in swimming pools. More particularly, it relates to friction feet which support swimming pool cleaners relative to and engagable with a surface to be cleaned.
Mechanical pool cleaners which utilize the flow of water drawn through the cleaner by means of a connecting flexible suction hose in communication with a filtration system pump are well known. Such pool cleaners are termed suction cleaners. Some suction cleaners include devices to establish reciprocating, impulsive, and vibratory forces useful for providing the propulsive force to move the cleaner in a random manner across the surface to be cleaned.
In U.S. Pat. No. 3,803,658 to Raubenheimer, an apparatus is disclosed which uses a repetitive variation in the flow of fluid through the apparatus to submit various components to variable loads and thereby impart stepwise movement to the apparatus across the surface to be cleaned.
A suction cleaner described in U.S. Pat. No. 4,023,227 to Chauvier uses the oscillatory movement of a flapper valve located in the operating head of the cleaner to impart impulsive forces to the apparatus for the purpose of moving the apparatus along the surface to be cleaned. U.S. Pat. Nos. 4,133,068 and 4,208,752 to Hofmann also use an oscillatable valve located in the head of the cleaner to provide impulsive forces to the apparatus for the purpose of moving the apparatus along the surface to be cleaned.
U.S. Pat. Nos. 4,682,833 and 4,742,593 to Stoltz and Kallenbach, respectively, disclose the use of an expansible tubular diaphragm to achieve a pulsating flow of fluid through the cleaner assembly and resultant forces suitable for the displacement of a pool cleaning apparatus over a surface to be cleaned.
Other means to provide impulsive, vibratory forces to a pool cleaner device are disclosed in U.S. Pat. No. 4,807,318 to Kallenbach, U.S. Pat. Nos. 4,769,867 and 4,817,225 to Stoltz and U.S. Pat. No. 5,404,607 to Sebor.
U.S. Pat. No 4,434,519 to Raubenheimer describes a suction cleaner having at least one friction support attached directly to the frame of the cleaner for engaging the submerged surface. The cleaner uses turbine means to impart reciprocating vibratory forces to the frame oblique to the submerged surface and alternately acting through the friction support in two opposed directions, the force in a first direction tending to lift the friction support from the surface and the force in the second direction tending to push the friction support back onto the surface, the resulting effect of said oblique forces and the bias caused by suction causing the apparatus to advance over the surface in a step by step manner. The friction support is a pivotally mounted foot projecting at an angle to the submerged surface and biased towards the vertical of said surface. Further improvements and a later embodiment of the aforementioned device were disclosed by Raubenheimer in U.S. Pat. No. 4,536,908.
U.S. Pat. No. 5,293,659 to Rief et al. discloses the use of a vibrator device and inclined bristle supports which work together to cause forward movement of the cleaner over the surface to be cleaned. Rief '659 discloses bristle supports inclined resilient supports. The term “resilient” is described as being the inherent characteristic of the support itself to bend. The bottom ends of the supports are offset from their corresponding top ends in a common direction.